1. Field of the Invention
The present invention relates to an actinic-ray-sensitive or radiation-sensitive resin composition which is preferably used in super-micro lithography processes such as the manufacture of VLSIs and high-capacity microchips, and other photo-fabrication processes, and a pattern forming method using the same. More specifically, the present invention relates to an actinic-ray-sensitive or radiation-sensitive resin composition that is especially suitable when an ArF excimer laser or a KrF excimer laser is used as an irradiation source, a resist film and a pattern forming method each using the composition, a method for preparing an electronic device, and an electronic device.
2. Description of the Related Art
In the production process for semiconductor devices, such as ICs and LSIs, it is conventional practice to perform microfabrication by lithography using a photoresist composition. In recent years, the formation of an ultrafine pattern in the submicron region or quarter-micron region has increasingly been demanded in accordance with the realization of high integration for integrated circuits. Accordingly, the trend of exposure wavelength toward a short wavelength, for example, from g rays to i rays, and further to KrF excimer laser light has been seen.
As a resist composition for KrF, those including a resin having a polyhydroxystyrene as a basic skeleton, have been developed. As such a resin, use of, for example, a copolymer including hydroxystyrene and a monomer containing an adamantyl group is known (see, for example, US2007/0121390A).
Meanwhile, as a resist composition for which an ArF light source is mainly used, the compositions including a resin containing no aromatic ring have been developed, and for example, the resist compositions including a resin having a specified lactone structure are known (see, for example, JP2008-031298A). Moreover, in order to improve adhesion to a substrate, resist compositions including a resin having a ketone structure are known (see, for example, JP3982950B and JP3504156B).
However, for the resist compositions, there are demands for improvement of line edge roughness (LER) and further improvement of inhibition of pattern collapse.